CCA-500 Online Practice Questions and Answers

Table schemas in Hive are:

A. Stored as metadata on the NameNode

B. Stored along with the data in HDFS

C. Stored in the Metadata

D. Stored in ZooKeeper

You observed that the number of spilled records from Map tasks far exceeds the number of map output records. Your child heap size is 1GB and your io.sort.mb value is set to 1000MB. How would you tune your io.sort.mb value to achieve maximum memory to disk I/O ratio?

A. For a 1GB child heap size an io.sort.mb of 128 MB will always maximize memory to disk I/O

B. Increase the io.sort.mb to 1GB

C. Decrease the io.sort.mb value to 0

D. Tune the io.sort.mb value until you observe that the number of spilled records equals (or is as close to equals) the number of map output records.

Identify two features/issues that YARN is designated to address: (Choose two)

A. Standardize on a single MapReduce API

B. Single point of failure in the NameNode

C. Reduce complexity of the MapReduce APIs

D. Resource pressure on the JobTracker

E. Ability to run framework other than MapReduce, such as MPI

F. HDFS latency

Which is the default scheduler in YARN?

A. YARN doesn't configure a default scheduler, you must first assign an appropriate scheduler class in yarn-site.xml

B. Capacity Scheduler

C. Fair Scheduler

D. FIFO Scheduler

Which YARN daemon or service negotiations map and reduce Containers from the Scheduler, tracking their status and monitoring progress?

A. NodeManager

B. ApplicationMaster

C. ApplicationManager

D. ResourceManager

You suspect that your NameNode is incorrectly configured, and is swapping memory to disk. Which Linux commands help you to identify whether swapping is occurring? (Select all that apply)

A. free

B. df

C. memcat

D. top

E. jps

F. vmstat

G. swapinfo

On a cluster running CDH 5.0 or above, you use the hadoop fs put command to write a 300MB file into a previously empty directory using an HDFS block size of 64 MB. Just after this command has finished writing 200 MB of this file, what would another use see when they look in directory?

A. The directory will appear to be empty until the entire file write is completed on the cluster

B. They will see the file with a ._COPYING_ extension on its name. If they view the file, they will see contents of the file up to the last completed block (as each 64MB block is written, that block becomes available)

C. They will see the file with a ._COPYING_ extension on its name. If they attempt to view the file, they will get a ConcurrentFileAccessException until the entire file write is completed on the cluster

D. They will see the file with its original name. If they attempt to view the file, they will get a ConcurrentFileAccessException until the entire file write is completed on the cluster

Your cluster has the following characteristics:

A rack aware topology is configured and on

Replication is set to 3

Cluster block size is set to 64MB

Which describes the file read process when a client application connects into the cluster and requests a 50MB file?

A. The client queries the NameNode for the locations of the block, and reads all three copies. The first copy to complete transfer to the client is the one the client reads as part of hadoop's speculative execution framework.

B. The client queries the NameNode for the locations of the block, and reads from the first location in the list it receives.

C. The client queries the NameNode for the locations of the block, and reads from a random location in the list it receives to eliminate network I/O loads by balancing which nodes it retrieves data from any given time.

D. The client queries the NameNode which retrieves the block from the nearest DataNode to the client then passes that block back to the client.

Your Hadoop cluster is configuring with HDFS and MapReduce version 2 (MRv2) on YARN. Can you configure a worker node to run a NodeManager daemon but not a DataNode daemon and still have a functional cluster?

A. Yes. The daemon will receive data from the NameNode to run Map tasks

B. Yes. The daemon will get data from another (non-local) DataNode to run Map tasks

C. Yes. The daemon will receive Map tasks only

D. Yes. The daemon will receive Reducer tasks only

You have A 20 node Hadoop cluster, with 18 slave nodes and 2 master nodes running HDFS High Availability (HA). You want to minimize the chance of data loss in your cluster. What should you do?

A. Add another master node to increase the number of nodes running the JournalNode which increases the number of machines available to HA to create a quorum

B. Set an HDFS replication factor that provides data redundancy, protecting against node failure

C. Run a Secondary NameNode on a different master from the NameNode in order to provide automatic recovery from a NameNode failure.

D. Run the ResourceManager on a different master from the NameNode in order to load-share HDFS metadata processing

E. Configure the cluster's disk drives with an appropriate fault tolerant RAID level

Your cluster implements HDFS High Availability (HA). Your two NameNodes are named nn01 and nn02. What occurs when you execute the command: hdfs haadmin failover nn01 nn02?

A. nn02 is fenced, and nn01 becomes the active NameNode

B. nn01 is fenced, and nn02 becomes the active NameNode

C. nn01 becomes the standby NameNode and nn02 becomes the active NameNode

D. nn02 becomes the standby NameNode and nn01 becomes the active NameNode

You have just run a MapReduce job to filter user messages to only those of a selected geographical region. The output for this job is in a directory named westUsers, located just below your home directory in HDFS. Which command gathers these into a single file on your local file system?

A. Hadoop fs getmerge R westUsers.txt

B. Hadoop fs getemerge westUsers westUsers.txt

C. Hadoop fs cp westUsers/* westUsers.txt

D. Hadoop fs get westUsers westUsers.txt

In CDH4 and later, which file contains a serialized form of all the directory and files inodes in the filesystem, giving the NameNode a persistent checkpoint of the filesystem metadata?

A. fstime

B. VERSION

C. Fsimage_N (where N reflects transactions up to transaction ID N)

D. Edits_N-M (where N-M transactions between transaction ID N and transaction ID N)

You have a cluster running with a FIFO scheduler enabled. You submit a large job A to the cluster, which

you expect to run for one hour. Then, you submit job B to the cluster, which you expect to run a couple of

minutes only.

You submit both jobs with the same priority.

Which two best describes how FIFO Scheduler arbitrates the cluster resources for job and its tasks?

(Choose two)

A. Because there is a more than a single job on the cluster, the FIFO Scheduler will enforce a limit on the percentage of resources allocated to a particular job at any given time

B. Tasks are scheduled on the order of their job submission

C. The order of execution of job may vary

D. Given job A and submitted in that order, all tasks from job A are guaranteed to finish before all tasks from job B

E. The FIFO Scheduler will give, on average, and equal share of the cluster resources over the job lifecycle

F. The FIFO Scheduler will pass an exception back to the client when Job B is submitted, since all slots on the cluster are use

A user comes to you, complaining that when she attempts to submit a Hadoop job, it fails. There is a Directory in HDFS named /data/input. The Jar is named j.jar, and the driver class is named DriverClass.

She runs the command:

Hadoop jar j.jar DriverClass /data/input/data/output

The error message returned includes the line: PriviligedActionException as:training (auth:SIMPLE) cause:org.apache.hadoop.mapreduce.lib.input.invalidInputException: Input path does not exist: file:/data/input

What is the cause of the error?

A. The user is not authorized to run the job on the cluster

B. The output directory already exists

C. The name of the driver has been spelled incorrectly on the command line

D. The directory name is misspelled in HDFS

E. The Hadoop configuration files on the client do not point to the cluster